Detector

ABSTRACT

A detector having an electronic arming delay timer, an antidisturbance firing mechanism, and a disconnect firing mechanism, wherein either firing mechanism is capable of causing detonation of a squib.

United States Patent West 51 May 30, 1972 [54} DETECTOR [56] References Clted [72] lnventor: Gaylon L. West, China Lake, Calif. NI E STATES PATENTS [73] Assignee: The United States of America as 3,343,493 9/1967 Aulds et al... l02/70.2 represented by the Secretary of the Navy 3,531,691 9/1970 Sitler et al l02/70.2

[22] Filed: 1970 Primary Examiner-Benjamin A. Borchelt 2 A l. N 1 01 21 ASSI'SMNI Examiner-J. J. Devitt I pp 0 Attorney-R. S. Sciascia, Roy Miller and Robert W. Adams [52] US. Cl ..l02/70.2, l02/l9.2 ABSTRACT [51] lnt.CI ..F42b 9/08, F42b 23/26 A detector having an electronic arming delay timer an [58] Field of Search ..102/70.2, 8, 16, 19.2 disturbance firin mechanism and a disconnect fi i mechanism, wherein either firing mechanism is capable of causing detonation of a squib.

4 Claims, 2 Drawing figures ANTI- DISTURBANCE ACTUATOR 12 18 1O 20 TIME FIRlNG DELAY CIRCUIT OUTPUT DISCONNECT ACTUATOR 2 Sheets-She et l ANTI- DISTURBANCE ACTUATOR 2O E FIRING DELAY CIRCUIT OUTPUT DISCONNECT ACTUATOR FIG. '5.

INVEN'IUK GAY LON L. WEST BY ROY MILLER ROBERT W. ADAMS ATTORNEYS.

DETECTOR STATEMENT OF GOVERNMENT INTEREST The invention described hereinmay be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION It is desirable to have a detector that cannot detonate during handling, and once armed, is not capable of being disarmed. Such a detector should additionally provide a safety feature which would delay arming for a preselected period of time after the means for arming is initiated.

Prior detectors initiate detonation upon completion of an electric circuit, such as by a trembler switch closing in response to movement. Additionally, detonation initiated by prior devices results from the gating action of parallel connected silicon controlled rectifier-s.

SUMMARY OF THE INVENTION The present invention is an improvement over and a modification of the device disclosed in U.S. Pat. Application Ser. No. 786,838 by Gaylon L. West et al., now U.S. Pat. No. 3,598,056, issued Aug. 10, 1971.

In accordance with the present invention, an electronic arming timer comprising a resistor and a capacitor is initiated upon closing an enabling switch. At the conclusion of the arming timing cycle the capacitor is charged, and the detector is armed and ready for detonation.

Detonation will occur in response to a disturbance resulting in movement of a trembler switch, or in response to an open circuit resulting from disconnection.

Either actuator triggers a silicon controlled rectifier, which in turn triggers a second silicon controlled rectifier, which applies the charge on a capacitor to a squib to cause detonation. Triggering the second SCR by the output of the first eliminates the possibility of accidental detonation.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram of the present invention; and FIG. 2 is a schematic diagram of the preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the present invention has an enabling switch 10, an electronic time delay 12, an antidisturbance actuator 14, a disconnect actuator 16, and a firing circuit 18 providing electric signal output 20. Actuation of antidisturbance actuator 14 or disconnect actuator 16 a predetermined period of time, controlled by time delay 12, after enabling switch is closed causes firing circuit 18 to provide an electric signal output 20.

Referring to FIG. 2, a schematic diagram of the preferred embodiment, including enabling switch 10, electronic time delay 12, antidisturbance actuator l4, disconnect actuator 16, firing circuit 18, and output 20, is shown.

Electronic time delay 12 consists of capacitor26 and resistor 24 connected in series. As is well known in the art the arming time delay is determined by the capacitive and resistive values of capacitor 26 and resistor 24.

Antidisturbance actuator 14 consists of resistor 48, capacitor 44, and trembler switch 42 connected in series with diode 46. Diode 46 prevents reverse current and possible premature detonation.

Disconnect actuator 16 consist of field effect transistor 32, capacitor 34, zener diode 36, resistors 38 and 40, and break wire 30. Break wire 30 operates to ground the gate of F ET 32.

Resistors 38 and 40 to operate as a voltage divider network to restrict the signal provided to the gate of SCR 54.

Firing circuit 18 consists of SCRs 54 and 64; resistors 56, 60, 62, and 66; and capacitors 52, 58 68, and 70. It should be noted that the gate of SCR 64 is coupled to the cathode of SCR 54. As a result, output 20 will be provided only when both SCR 64 and SCR 54 are conducting.

The operation is as follows: When enabling switch 10 is closed power supply 22 provides current through resistor 24 to capacitor 26 and resistor 28 connected in parallel. As above mentioned, together capacitor 26 and resistor 24 cause an arming time delay.

When armed, the firing circuit 18 can be actuated by antidisturbance actuator 14 or disconnect actuator 16. In either case a voltage is applied to the gate of SCR 54 causing it to conduct.

If the detector is moved trembler switch 42 will complete the circuit between capacitor 44 and the gate of SCR 54. The voltage stored on capacitor 44 will then appear at the gate of SCR 54, switching it to its conductive state.

If break line 30 is disconnected the gate of FET 32 will no longer be grounded. Capacitor 34 will then charge. When the voltage on capacitor 34 is of sufiicient magnitudevzener diode 36 will break down allowing FET 32 to conduct. As the result, a positive voltage will appear at thegate of SCR 54, likewise switching it to its conductive state.

When SCR 54 is conducting a positive voltage appears at the gate of SCR 64, switching it to its conductive state. When in its conductive state, SCR 64 supplies the voltage on capacitors 68 and '70 to output 20.

While applicant does not wish to be limited to any particular set of circuit constants, the following constants have proven to be useful in the particular circuit shown.

Symbol Components Type or Value 22 Power supply 30 volts 24 Resistor 330 ohm 26 Capacitor 5 microfarad 28 Resistor 20 megohm 32 Field effect transistor 2N389l l9 Capacitor 0.0l microfarad 36 Diode M4L 3054 38 Resistor 20 kilohm 40 Resistor l0 kilohm 44 Capacitor 5 microfarad 46 Diode M4L 3054 48 Resistor 270 kilohm 50 Lamp CM8l570 52 Capacitor i200 picofarad 54 Silicon controlled rectifier 2N885 56 Resistor 430 ohm 58 Capacitor 5 microfarad 60 Resistor 4.7 kilohm 62 Resistor l megohm 64 Silicon controlled rectifier 2N885 66 Resistor l.2 kilohm 68 Capacitor microfarad 70 Capacitor I00 microfarad For testing, the squib or other detonator connected to output 20 is removed. Hence, when either trembler switch 42 or break line 30 is actuated the current through SCR 54 will cause lamp 50 to light, indicating that the antidisturbance actuator or the disconnect actuator and the remaining electronic circuitry are operating correctly.

What is claimed is:

l. A detector for detecting disturbances resulting in movement or electrical circuit disconnection, comprising:

means for initiating an electronic time delay;

an electronic time delay to delay arming the detector for a predetermined period of time;

antidisturbance means for actuating a firing circuit in response to a disturbance resulting in movement of said antidisturbance means at any time after said predetermined period of time;

circuit means for actuating said firing circuit in response to an electrical disconnection in said circuit means at any time after said predetermined period of time; and

a firing circuit coupled to said antidisturbance means and said circuit means, wherein said firing circuit provides an electric signal output when actuated by said antidisturbance means or said circuit means.

2. The detector of claim 1 wherein said firing circuit comprises;

a first silicon controlled rectifier coupled to said antidisturbance means and said circuit means, and

a second silicon controlled rectifier wherein the gate of said second silicon controlled rectifier is coupled to the cathode of said first silicon controlled rectifier.

3. The detector of claim 1 wherein said circuit means comprises;

a field effect transistor,

a break wire coupled to the gate of said field effect transistor,

a capacitor coupled to the gate of said field effect transistor in parallel with said break wire,

a zener diode coupled to the drain of said field effect transistor, and

5 a voltage divider network coupled to said zener diode,

such that when said break wire is disconnected said firing circuit will be actuated. 4. The detector of claim 3 wherein said firing circuit com- 1 O prises;

a first silicon controlled rectifier coupled to said antidisturbance means and said circuit means, and a second silicon controlled rectifier wherein the gate of said second silicon controlled rectifier is coupled to the 1 5 cathode of said first silicon controlled rectifier.

I II I It i 

1. A detector for detecting disturbances resulting in movement or electrical circuit disconnection, comprising: means for initiating an electronic time delay; an electronic time delay to delay arming the detector for a predetermined period of time; antidisturbance means for actuating a firing circuit in response to a disturbance resulting in movement of said antidisturbance means at any time after said predetermined period of time; circuit means fOr actuating said firing circuit in response to an electrical disconnection in said circuit means at any time after said predetermined period of time; and a firing circuit coupled to said antidisturbance means and said circuit means, wherein said firing circuit provides an electric signal output when actuated by said antidisturbance means or said circuit means.
 2. The detector of claim 1 wherein said firing circuit comprises; a first silicon controlled rectifier coupled to said antidisturbance means and said circuit means, and a second silicon controlled rectifier wherein the gate of said second silicon controlled rectifier is coupled to the cathode of said first silicon controlled rectifier.
 3. The detector of claim 1 wherein said circuit means comprises; a field effect transistor, a break wire coupled to the gate of said field effect transistor, a capacitor coupled to the gate of said field effect transistor in parallel with said break wire, a zener diode coupled to the drain of said field effect transistor, and a voltage divider network coupled to said zener diode, such that when said break wire is disconnected said firing circuit will be actuated.
 4. The detector of claim 3 wherein said firing circuit comprises; a first silicon controlled rectifier coupled to said antidisturbance means and said circuit means, and a second silicon controlled rectifier wherein the gate of said second silicon controlled rectifier is coupled to the cathode of said first silicon controlled rectifier. 